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<!--     <script>
        prompt('数量');
        // 输入框
        let num ='20件';
        let uname ='张三';
        // 快速声明两个变量：let 变量名 =（数值或文字）
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    <script>
        let na ='222';
        let na1 ='333';
        let na2='335';
        console.log(na,na1,na2);
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